Re: Need S-RAMs for ZipGS!

[spec@vax2.concordia.ca (Mitchell Spector)]

In article pubpc1@library.ucla.edu writes...

>How fast have you gotten the Zip to go with 70ns in DATA and
>15ns in TAG?  I've seen a board go 12.5MHz with that combination.
>Also, if you have stability problems, you can try moving the
>cache settings progressively from 64K to 32K to 16K to 8K.
>I have 64K installed, but at 13.75MHz, the Zip would not stabilize
>until the board was set to 16K (even though 64K were installed).
>Since I made comparisons of performance using the MegaDemo, which
>showed that performance levels off at 16K of cache, this was ok. :)

    I experienced the same, at 15 MHz things would not run stable 
with 64K of cache enabled, but dropping it down to 32K cache did
help make things run smoothly. Since then, a heat sink placed over
the ASIC has allowed me to run the board as a 15/64 again (most 
Pentium-sized CPU heat sinks will fit over the ASIC if placed 
just right. Just make sure it fits perfectly flat over the ASIC
and there is no contact with any pins or anything else which may
cause a short. I found one that fits like a glove and wedges 
nicely between the oscillator and PLCC CPU socket).

    If it would have helped, I'd probably have dropped a lucky 
rabbit's foot over the Zip to get it running stable. ;) 

Mitchell Spector
spec@vax2.concordia.ca